Where will all that dirt go? Here’s the scoop

Crews removed more than 86,000 cubic yards of soil during construction of the recently completed SR 99 tunnel launch pit. That may seem like a lot, but it’s nothing compared with the 850,000 cubic yards of soil that will be removed by Bertha, the SR 99 tunneling machine, as she digs her way beneath Seattle.

How much is 850,000 cubic yards of soil? Put it this way: If, just for fun, you decided to pile it all on top of the turf at nearby CenturyLink Field, your pile would be about 400 feet tall – more than 100 feet taller than the stadium’s roof. But we wouldn’t do that. Instead, contaminated soil is hauled by truck to a nearby transfer station, while clean soil is trucked to one of several area disposal facilities.

When tunneling starts this summer, soil excavated by Bertha will be removed via a conveyor belt that extends from the tunnel to barges waiting at Terminal 46. The barges will take the soil across Puget Sound to a large reclamation site near Port Ludlow. There, our nice Seattle soil, along with soil removed during tunneling for King County’s Brightwater Project, will be used to fill in an old quarry.